1. Field of the Invention
The present invention relates to a method for acquiring an image for inspection of a flat panel display which can be advantageously used in inspecting a pixel defect, an uneven display or the like of a flat panel display such as, for example, a liquid crystal display (LCD), a plasma display (PDP) or the like, and to an apparatus for acquiring an image for inspection of such flat panel display using this method.
2. Description of the Related Art
An apparatus for inspecting quality of a picture or an image of a flat panel display (an image quality inspection apparatus for a flat panel display) such as a liquid crystal display, a plasma display or the like mainly comprises an inspection image acquisition apparatus for acquiring an image data for inspection, and an image quality inspection apparatus for inspecting whether or not any pixel defect (loss), an uneven display, or the like exists, using an image data acquired by this inspection image acquisition apparatus.
FIG. 17 is a block diagram showing a general construction of the portion of an inspection image acquisition apparatus in the image quality inspection apparatus for a flat panel display. As illustrated, this inspection image acquisition apparatus comprises a panel driver part 2 for driving a flat panel display (for example, a liquid crystal display) 8 to be inspected, a camera part 3 having a camera (for example, a CCD (charge coupled device) camera) therein for photographing (picking up as an image) a displayed image on the flat panel display 8, an analog-to-digital (AD) converter 4 for converting a photographed analog image signal from the camera part 3 into a digital signal, an image memory 7 for storing therein the converted digital image signal, a pre-sampling processing part 5 for pre-sampling the digital image signal and converting the pre-sampled digital image signal into an image data in which each pixel thereof has the same size as that of the display screen (panel) of the flat panel display 8, and a control part 1 for directly controlling the panel driver part 2 as well as controlling the AD converter 4, the pre-sampling processing part 5 and the image memory 7 via a bus (BUS).
The flat panel display 8 to be inspected displays on its panel a test image or picture having a predetermined light and darkness (shade) based on a driving signal outputted from the panel driver part 2 under the control of the control part 1 (usually constituted by a CPU). The light and darkness image of the flat panel display 8 is photographed (picked up as an image) by the camera (solid state image pickup element) of the camera part 3 to supply it to the AD converter 4. The analog image signal from the camera part 3 is converted by the AD converter 4 into digital pixel data of light and darkness (hereinafter, referred to as pickup pixel data), which is in turn temporarily stored in the image memory 7.
The pickup pixel data converted into a digital signal is pre-sampled by the pre-sampling processing part 5, and is converted into an image data in which each pixel thereof has the same size as that of the panel of the flat panel display 8. The converted image data is hereinafter referred to as pre-sampling image data or a display pixel data. The converted display pixel data is stored in the image memory 7. Further, since the method for converting pickup pixel data to pre-sampling image data is described in detail in Japanese Patent Applications (refer to Japanese Patent Application Laid Open No. Hei 8-29360 (29360/1996) and Japanese Patent Application Laid Open No. Hei 10-31730 (31730/1998)) previously proposed by the present applicants, reference should be made to those Japanese Patent Applications or Japanese Patent Application Laid Open Publications thereof. In addition, the descriptions of those Japanese Patent Applications are incorporated into the present specification.
In order to suppress the occurrence of any moirxc3xa9 in the display pixel data obtained by converting an analog image signal picked up by the camera part 3 into digital pickup pixel data and applying the pre-sampling processing to the pickup pixel data with higher accuracy, it is desired that the pixel magnification is an integer magnification such as two times or so. Here, the pixel magnification is defined as a ratio of the number of pixels of the panel of the flat panel display 8 to the number of pixels of the solid state image pickup element (for example, CCD element) of the camera part 3. As an example, the condition that one pixel of the panel of the flat panel display 8 is photographed or picked up by 2xc3x972 pixels of the solid state image pickup element of the camera part 3 is said that the pixel magnification is two.
However, with the progress of a fine pitched and high precision flat panel display 8, and by a limitation of pixel size of the camera part 3 on the other side, there often occurs a case that the pixel magnification to be set is unavoidably set to a non-integer magnification less than 2.
When the pixel magnification is set to a non-integer magnification less than 2, a periodic pixel value fluctuation occurs in each of the pickup pixel data and the pre-sampling image data or display pixel data, the pickup pixel data being acquired by the camera part 3 and being converted into digital data, the display pixel data being obtained by applying a pre-sampling processing to the pickup pixel data. This periodic pixel value fluctuation is called moirxc3xa9 of image. FIG. 18 shows an example of the result obtained by that in case of setting the pixel magnification to 1.8, pixel values (each corresponding to brightness of a pixel) of the display pixel data acquired by the camera part 3 and stored in the image memory 7 are summed up, for the same X address (X address is defined as horizontal or lateral axis herein), in Y address direction (vertical or longitudinal axis direction). In FIG. 18, it is recognized that a moirxc3xa9 of approximately five-pixel period has occurred, that is, a moirxc3xa9 occurs approximately at intervals of five pixels. There is a problem that this moirxc3xa9 comes to a noise component, resulting in great decrease in the inspection accuracy of the flat panel display 8.
The moirxc3xa9 of an image has already occurred in the state that the distribution of light intensity of the flat panel display 8 is sampled by pixels of the image pickup element (for example, CCD) of the camera part 3. This is primarily caused by that the difference of relative position between a display pixel of the flat panel display 8 and a pixel of the image pickup element of the camera part 3 is reflected to the display pixel data (pre-sampling image data). Further, hereinafter, a pixel of the image pickup element of the camera part 3 is referred to as a pickup pixel, and a display pixel of the panel of the flat panel display 8 is referred to as a display pixel.
FIG. 19 shows an example of relative position between a pickup pixel and a display pixel in the case of the pixel magnification of 1.8. In this example, the pickup pixels are pixels of the CCD image pickup element, and the display pixels are display pixels of the panel of a liquid crystal display (LCD). Further, in this case, in order to simplify the explanation, the description will be given based on a one-dimensional signal.
Since the pixel magnification is 1.8, as shown in FIG. 19A, 9 pixels of the pickup pixels correspond to 5 pixels of the display pixels, and this positional relationship is periodically repeated. The sampling values G(n) (n is an integer from 1 to 10) (refer to FIG. 19C), in this case, sampled by the first to the tenth pickup pixels with respect to the periodic light intensity distribution g(x) (refer to FIG. 19B) of the display pixels are shown by the following equation (1).                                                                                           G                  ⁡                                      (                    1                    )                                                  =                                                      ∫                                          x                      0                                                              x                      1                                                        ⁢                                                            g                      ⁡                                              (                                                  x                          -                                                                                                                    x                                0                                                            +                                                              x                                2                                                                                      2                                                                          )                                                              ⁢                                          xe2x80x83                                        ⁢                                          ⅆ                      x                                                                                                                                                                G                  ⁡                                      (                    2                    )                                                  =                                                                            ∫                                              x                        1                                                                    x                        2                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  0                                                                +                                                                  x                                  2                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                              +                                                            ∫                                              x                        2                                                                    x                        3                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  2                                                                +                                                                  x                                  5                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                                                                                                                                      G                  ⁡                                      (                    3                    )                                                  =                                                      ∫                                          x                      3                                                              x                      4                                                        ⁢                                                            g                      ⁡                                              (                                                  x                          -                                                                                                                    x                                2                                                            +                                                              x                                5                                                                                      2                                                                          )                                                              ⁢                                          xe2x80x83                                        ⁢                                          ⅆ                      x                                                                                                                                                                G                  ⁡                                      (                    4                    )                                                  =                                                                            ∫                                              x                        4                                                                    x                        5                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  2                                                                +                                                                  x                                  5                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                              +                                                            ∫                                              x                        5                                                                    x                        6                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  5                                                                +                                                                  x                                  8                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                                                                                                                                      G                  ⁡                                      (                    5                    )                                                  =                                                      ∫                                          x                      6                                                              x                      7                                                        ⁢                                                            g                      ⁡                                              (                                                  x                          -                                                                                                                    x                                5                                                            +                                                              x                                8                                                                                      2                                                                          )                                                              ⁢                                          xe2x80x83                                        ⁢                                          ⅆ                      x                                                                                                                                                                G                  ⁡                                      (                    6                    )                                                  =                                                                            ∫                                              x                        7                                                                    x                        8                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  5                                                                +                                                                  x                                  8                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                              +                                                            ∫                                              x                        8                                                                    x                        9                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  8                                                                +                                                                  x                                  11                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                                                                                                                                      G                  ⁡                                      (                    7                    )                                                  =                                                      ∫                                          x                      9                                                              x                      10                                                        ⁢                                                            g                      ⁡                                              (                                                  x                          -                                                                                                                    x                                8                                                            +                                                              x                                11                                                                                      2                                                                          )                                                              ⁢                                          xe2x80x83                                        ⁢                                          ⅆ                      x                                                                                                                                                                G                  ⁡                                      (                    8                    )                                                  =                                                                            ∫                                              x                        10                                                                    x                        11                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  8                                                                +                                                                  x                                  11                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                              +                                                            ∫                                              x                        11                                                                    x                        12                                                              ⁢                                                                  g                        ⁡                                                  (                                                      x                            -                                                                                                                            x                                  11                                                                +                                                                  x                                  13                                                                                            2                                                                                )                                                                    ⁢                                              xe2x80x83                                            ⁢                                              ⅆ                        x                                                                                                                                                                                      G                  ⁡                                      (                    9                    )                                                  =                                                      ∫                                          x                      12                                                              x                      13                                                        ⁢                                                            g                      ⁡                                              (                                                  x                          -                                                                                                                    x                                11                                                            +                                                              x                                13                                                                                      2                                                                          )                                                              ⁢                                          xe2x80x83                                        ⁢                                          ⅆ                      x                                                                                                                                                                G                  ⁡                                      (                    10                    )                                                  =                                                      ∫                                          x                      13                                                              x                      14                                                        ⁢                                                            g                      ⁡                                              (                                                  x                          -                                                                                                                    x                                13                                                            +                                                              x                                15                                                                                      2                                                                          )                                                              ⁢                                          xe2x80x83                                        ⁢                                          ⅆ                      x                                                                                                          }                            (        1        )            
From the periodic nature of the relative position between a pickup pixel (CCD) and a display pixel (LCD), the positional relationship between the display pixel 6 and the pickup pixel 10 in FIG. 19A is equal to the positional relationship between the display pixel 1 and the pickup pixel 1. That is, since the positions of x14 and x15 relative to X13 are equal to the positions of the x1 and x2 relative to x0, the pixel value G(1) is equal to the pixel value G(10). Therefore, the sampling values by pickup pixels shown in FIG. 19C have nine patterns depending upon differences of the relative positions, and those nine patterns are repeated periodically. Those sampling values by pickup pixels become an output signal of the camera part 3. Accordingly, in the pickup image data which is a digital signal converted from the output signal, there occurs a moirxc3xa9 in which the nine patterns of the sampling values G(1)-G(9) periodically repeat.
Next, a case of pre-sampling the sampling values G(1)-G(9) by the pickup pixels in correspondence to the size of the display pixel will be discussed. The relationship between the sampling values G(1)-G(9) by the pickup pixels and the pre-sampling intervals is as shown in FIG. 19C. The area of the sampling value by the pickup pixel (CCD) in each of the pre-sampling intervals x0-x2, x2-x5, x5-x8, and x8-x11 becomes a pixel value of the display image data corresponding to the size of display pixel (LCD). Therefore, the pixel values f(n) (n is an integer from 1 to 6) corresponding to the first to the sixth display pixels by pre-sampling processing can be expressed by a next equation (2).                                                                                           f                  ⁡                                      (                    1                    )                                                  =                                                      G                    ⁡                                          (                      1                      )                                                        +                                                                                                              x                          2                                                -                                                  x                          1                                                                                                                      x                          3                                                -                                                  x                          1                                                                                      ⁢                                          G                      ⁡                                              (                        2                        )                                                                                                                                                                                      f                  ⁡                                      (                    2                    )                                                  =                                                                                                                              x                          3                                                -                                                  x                          2                                                                                                                      x                          3                                                -                                                  x                          1                                                                                      ⁢                                          G                      ⁡                                              (                        2                        )                                                                              +                                      G                    ⁡                                          (                      3                      )                                                        +                                                                                                              x                          5                                                -                                                  x                          4                                                                                                                      x                          6                                                -                                                  x                          4                                                                                      ⁢                                          G                      ⁡                                              (                        4                        )                                                                                                                                                                                      f                  ⁡                                      (                    3                    )                                                  =                                                                                                                              x                          6                                                -                                                  x                          5                                                                                                                      x                          6                                                -                                                  x                          4                                                                                      ⁢                                          G                      ⁡                                              (                        4                        )                                                                              +                                      G                    ⁡                                          (                      5                      )                                                        +                                                                                                              x                          8                                                -                                                  x                          7                                                                                                                      x                          9                                                -                                                  x                          7                                                                                      ⁢                                          G                      ⁡                                              (                        6                        )                                                                                                                                                                                      f                  ⁡                                      (                    4                    )                                                  =                                                                                                                              x                          9                                                -                                                  x                          8                                                                                                                      x                          9                                                -                                                  x                          7                                                                                      ⁢                                          G                      ⁡                                              (                        6                        )                                                                              +                                      G                    ⁡                                          (                      7                      )                                                        +                                                                                                              x                          11                                                -                                                  x                          10                                                                                                                      x                          12                                                -                                                  x                          10                                                                                      ⁢                                          G                      ⁡                                              (                        8                        )                                                                                                                                                                                      f                  ⁡                                      (                    5                    )                                                  =                                                                                                                              x                          12                                                -                                                  x                          11                                                                                                                      x                          12                                                -                                                  x                          10                                                                                      ⁢                                          G                      ⁡                                              (                        8                        )                                                                              +                                      G                    ⁡                                          (                      9                      )                                                                                                                                                                f                  ⁡                                      (                    6                    )                                                  =                                                      G                    ⁡                                          (                      10                      )                                                        +                                                                                                              x                          15                                                -                                                  x                          14                                                                                                                      x                          16                                                -                                                  x                          14                                                                                      ⁢                                          G                      ⁡                                              (                        11                        )                                                                                                                                }                            (        2        )            
Also in the equation (2), from the periodic nature of the relative position between the pickup pixel and the display pixel, f(1) is equal to f(6). As a result, the pixel values of a display pixel data corresponding to display pixels have five patterns, and those patterns are repeated. Consequently, it should be understood that when in the case that the pixel magnification is 1.8, a moirxc3xa9 occurs in the pre-sampling image data with a five-pixel period, that is, at intervals of five pixels. As mentioned above, there is a serious disadvantage that the moirxc3xa9 comes to a noise component, which results in great decrease in the inspection accuracy of the flat panel display 8.
It is an object of the present invention to provide an image acquisition method for inspection of a flat panel display which can eliminate any moirxc3xa9 component.
It is another object of the present invention to provide an image acquisition apparatus for inspection of a flat panel display using the above image acquisition method, which can be advantageously used in inspecting at high accuracy whether any defect exists in the flat panel display or not.
In order to accomplish the above objects, in a first aspect of the present invention, there is provided a method for acquiring an image for inspection of a flat panel display including the steps of: displaying an image for inspection on a flat panel display to be inspected, and picking up the inspection image by a solid state image pickup element to convert the pickup image signal to a digital signal, thereby to obtain pickup pixel data each pixel of which has a pixel value corresponding to the pixel size of said solid state image pickup element; and applying a pre-sampling processing to the pickup pixel data, thereby to obtain display pixel data each pixel of which has a pixel value corresponding to the pixel size of said flat panel display, and said method further including the steps of: storing the display pixel data in an image memory; obtaining a plurality of moirxc3xa9 component image data by detecting any moirxc3xa9 in respect to either direction of X-axis direction or Y-axis direction occurring in the display pixel data stored in said image memory, forming a plurality of data series, each data series being collected from the display pixel data at intervals of the number of pixels of the display pixel data corresponding to the occurrence period of the moirxc3xa9, the number of said plurality of data series depending upon the number of pixels included within the occurring period of the moirxc3xa9, and smoothing pixel values of each of the plurality of data series, thereby to obtain a plurality of moirxc3xa9 component image data from which defect components have been eliminated; taking a difference between the moirxc3xa9 component image data and the display pixel data to find defect component image data; storing the defect component image data in a defect component image memory; giving a pixel value to a pixel having no pixel value in each moire component image data by an interpolation operation, and finding a mutual average value of the plurality of the moirxc3xa9 component image data to obtain smoothed image data from which the moire has been eliminated; and storing the smoothed image data in a smoothed image memory. The defect component image data stored in said defect component image memory and the smoothed image data stored in said smoothed image memory are maintained as image data for inspection of the flat panel display.
According to the image acquisition method for inspection of a flat panel display of the above first aspect, in the case that the direction of the moirxc3xa9 occurrence is either one of the X-axis direction or the Y-axis direction, the smoothed image data from which the moirxc3xa9 has been eliminated and the defect component image data can be obtained. These data are separately stored in the associated memories respectively, and hence it is possible to send them to an image quality inspection apparatus for a flat panel display separately.
In a second aspect of the present invention, the step of obtaining a plurality of moirxc3xa9 component image data sequentially detects any moirxc3xa9 in respect to both the X-axis and the Y-axis directions, and obtains a plurality of moirxc3xa9 component image data from which defect components have been eliminated in respect to both the X-axis and the Y-axis directions.
According to the image acquisition method for inspection of a flat panel display of the above second aspect, even in the case that the direction of the moirxc3xa9 occurrence is both of the X-axis direction and the Y-axis direction, the smoothed image data from which the moirxc3xa9 has been eliminated and the smoothed image data can be obtained for each direction. These data are separately stored in the associated memories respectively, and hence it is possible to send them to an image quality inspection apparatus for a flat panel display separately.
In a preferred embodiment, the image acquisition method further includes a step of adding the defect component image data and the smoothed image data, and storing the addition result in said image memory as image data for inspection of the flat panel display.
In this embodiment, the defect component image data and the smoothed image data are added, and the addition result is stored in the common image memory. Consequently, the addition result of the smoothed image data and the defect component image data is to be sent to an image quality inspection apparatus for a flat panel display.
In a third aspect of the present invention, there is provided a method for acquiring an image for inspection of a flat panel display including the steps of: displaying an image for inspection on a flat panel display to be inspected, and picking up the inspection image by a solid state image pickup element to convert the pickup image signal to a digital signal, thereby to obtain pickup pixel data each pixel of which has a pixel value corresponding to the pixel size of said solid state image pickup element; and applying a pre-sampling processing to the pickup pixel data, thereby to obtain display pixel data each pixel of which has a pixel value corresponding to the pixel size of said flat panel display, and said method further including the steps of: storing the pickup pixel data in an image memory; obtaining a plurality of moirxc3xa9 component image data by detecting any moirxc3xa9 in respect to either direction of X-axis direction or Y-axis direction occurring in the pickup pixel data stored in said image memory, forming a plurality of data series, each data series being collected from the pickup pixel data at intervals of the number of pixels of the pickup pixel data corresponding to the occurrence period of the moirxc3xa9, the number of said plurality of data series depending upon the number of pixels included within the occurring period of the moirxc3xa9, and smoothing pixel values of each of the plurality of data series, thereby to obtain a plurality of moirxc3xa9 component image data from which defect components have been eliminated; taking a difference between the moirxc3xa9 component image data and the pickup pixel data to find defect component image data; storing the defect component image data in a defect component image memory; giving a pixel value to a pixel having no pixel value in each moirxc3xa9 component image data by an interpolation operation, and finding a mutual average value of the plurality of the moirxc3xa9 component image data to obtain smoothed image data from which the moirxc3xa9 has been eliminated; storing the smoothed image data in a smoothed image memory; adding the defect component image data stored in said defect component image memory and the smoothed image data stored in said smoothed image memory; and applying a pre-sampling processing to the image data obtained in said adding step to obtain display pixel data each pixel of which has a pixel value corresponding to the pixel size of the flat panel display. The display pixel data obtained in said step of applying a pre-sampling processing is maintained as image data for inspection of the flat panel display.
According to the image acquisition method for inspection of a flat panel display of the above third aspect, before the pre-sampling processing is applied, any moirxc3xa9 in either one of the X-axis direction or the Y-axis direction is removed from the pickup pixel data, and thereafter the smoothed image data from which the moirxc3xa9 has been eliminated and the defect component image data are obtained. These data are summed up and the pre-sampling processing is applied to the summed image data to convert into the display pixel data each having the display pixel size. Accordingly, the display pixel data is to be sent to an image quality inspection apparatus for a flat panel display separately.
In a fourth aspect of the present invention, said step of obtaining a plurality of moirxc3xa9 component image data sequentially detects any moirxc3xa9 in respect to both the X-axis and the Y-axis directions, and obtains a plurality of moirxc3xa9 component image data from which defect components have been eliminated in respect to both the X-axis and the Y-axis directions.
According to the image acquisition method for inspection of a flat panel display of the above fourth aspect, before the pre-sampling processing is applied, any moirxc3xa9s in both directions of the X-axis direction and the Y-axis direction are removed from the pickup pixel data.
In a preferred embodiment, the method further includes the step of storing the display pixel data obtained in the step of applying a pre-sampling process in said image memory as image data for inspection of the flat panel display.
In a fifth aspect of the present invention, there is provided an apparatus for acquiring an image for inspection of a flat panel display comprising: a panel driver part for supplying a driving signal to a flat panel display to be inspected to display a predetermined test image on said flat panel display to be inspected; a camera part for picking up the test image displayed on said flat panel display as image data of light and darkness; an analog-to-digital converter for converting an output signal of said camera part into pickup pixel data constructed by digital image data of light and darkness; a pre-sampling processing part for applying a pre-sampling processing to the digital pickup pixel data to obtain display pixel data each pixel of which has a pixel value corresponding to the pixel size of the flat panel display; a moirxc3xa9 elimination processing part for eliminating any moirxc3xa9 occurring in the display pixel data obtained in said pre-sampling processing part; an image memory for storing therein the display pixel data from which the moirxc3xa9 has been eliminated by said moirxc3xa9 elimination processing part; and a control part for performing a sending/receiving control of data or driving control in each of the elements except said camera part.
In a preferred embodiment, said moirxc3xa9 elimination processing part comprises: a defect elimination processing part for smoothing pixel values of data collected, from a data series in either of the X-axis direction or the Y-axis direction of the display pixel data obtained in said pre-sampling processing part, at an interval corresponding to the occurring period of the moirxc3xa9, thereby to obtain moirxc3xa9 component image data from which any defect component has been eliminated; a moirxc3xa9 component image memory for storing therein the moirxc3xa9 component image data produced by said defect elimination processing part; a difference processing part for taking a difference between the display pixel data and the moirxc3xa9 component image data to obtain defect component image data; a defect component image memory for storing therein the defect component image data obtained in said difference processing part; an averaging process part for averaging the moirxc3xa9 component image data stored in said moirxc3xa9 component image memory mutually in respect to the data series in the X-axis direction or the Y-axis direction which is the same direction as that of said defect elimination processing part, thereby to obtain smoothed image data from which the moirxc3xa9 components have been eliminated; and a smoothed image memory for storing therein the smoothed image data obtained in said averaging process part.
In an another preferred embodiment, said defect elimination processing part further includes an addition processing part for adding the smoothed image data stored in said smoothed image memory and the defect component image data stored in said defect component image memory.
In addition, said defect elimination processing part is constructed such that a defect eliminating process in the X-axis direction is first performed and then a defect eliminating process in Y-axis direction is performed, thereby to eliminate moirxc3xa9s occurring in both the X-axis and the Y-axis directions. Alternatively, said defect elimination processing part may be constructed such that a defect eliminating process in the Y-axis direction is first performed and then a defect eliminating process in the X-axis direction is performed, thereby to eliminate moirxc3xa9s occurring in both the X-axis and the Y-axis directions.
According to the image acquisition apparatus for inspection of a flat panel display of the above fifth aspect, the image acquisition methods for inspection of a flat panel display of the first and the second aspects of the present invention can be carried out.
In a sixth aspect of the present invention, there is provided an apparatus for acquiring an image for inspection of a flat panel display comprising: a panel driver part for supplying a driving signal to a flat panel display to be inspected to display a predetermined test image on said flat panel display to be inspected; a camera part for picking up the test image displayed on said flat panel display as image data of light and darkness; an analog-to-digital converter for converting an output signal of said camera part into pickup pixel data constructed by digital image data of light and darkness; a moirxc3xa9 elimination processing part for eliminating any moirxc3xa9 produced in the digital pickup pixel data; an image memory for storing therein the pickup pixel data from which the moirxc3xa9 has been eliminated by said moirxc3xa9 elimination processing part; a pre-sampling processing part for applying a pre-sampling process to the pickup pixel data from which the moirxc3xa9 has been eliminated read out from said image memory, thereby to obtain display pixel data each pixel of which has a pixel value corresponding to the pixel size of the flat panel display; and a control part for performing a sending/receiving control of data or driving control in each of the elements except said camera part.
In a preferred embodiment, said moirxc3xa9 elimination processing part comprises: a defect elimination processing part for smoothing pixel values of data collected, from a data series in either of the X-axis direction or the Y-axis direction of pickup pixel data outputted from said analog-to-digital converter, at an interval corresponding to the occurring period of the moirxc3xa9, thereby to obtain moirxc3xa9 component image data from which any defect component has been eliminated; a moirxc3xa9 component image memory for storing therein the moirxc3xa9 component image data obtained in said defect elimination processing part; a difference processing part for taking the difference between the pickup pixel data and the moirxc3xa9 component image data to obtain defect component image data; a defect component image memory for storing therein defect component image data obtained in said difference processing part; an averaging process part for averaging the moirxc3xa9 component image data stored in said moirxc3xa9 component image memory mutually in respect to the data series in the X-axis direction or the Y-axis direction which is the same direction as that of said defect elimination processing part, thereby to obtain smoothed image data from which the moirxc3xa9 component has been eliminated; a smoothed image memory for storing therein the smoothed image data obtained in said averaging process part; and an addition processing part for adding the smoothed image data stored in said smoothed image memory and the defect component image data stored in said defect component image memory. The pre-sampling processing part applies a pre-sampling process to the image data added in said addition processing part to obtain display pixel data each pixel of which has a pixel value corresponding to the pixel size of the flat panel display.
In an another preferred embodiment, said defect elimination processing part is constructed such that a defect eliminating process in the X-axis direction is first performed and then a defect eliminating process in the X-axis direction is performed, thereby to eliminate moirxc3xa9s occurring in both the X-axis and the Y-axis directions. Alternatively, said defect elimination processing part may be constructed such that a defect eliminating process in the Y-axis direction is first performed and then a defect eliminating process in the X-axis direction is performed, thereby to eliminate moirxc3xa9s occurring in both the X-axis and the Y-axis directions.
According to the image acquisition apparatus for inspection of a flat panel display of the above sixth aspect, the image acquisition methods for inspection of a flat panel display of the third and the fourth aspects of the present invention can be carried out.